This invention relates to an oil cooler for internal combustion engines, with an oil circuit arranged in a housing with an oil inlet opening and an oil outlet opening, and with a cooling circuit.
Oil coolers customarily comprise a substantially parallelepiped housing having inlet and outlet conduits for the oil to be cooled, and inlet and outlet conduits for the coolant. Such an oil cooler with a stacked-disk construction is described in U.S. Pat. No. 5,927,394, and includes of several trough-like plates that are stacked together at intervals and soldered so that their upright edges form adjacent hollow chambers.
An oil cooler can be fastened to a side of an engine block (such as shown in U.S. Pat. No. 4,793,302), or it can be fastened to a component of the vehicle body (such as shown in published German patent DE 40 23 042 A1). But, space for the housing of an oil cooler is limited in the engine area. Moreover, a structure which improves heat exchange between the oil to be cooled and the liquid coolant is also desired.
An object of the present invention is to provide an oil cooler which has a size and structure so that it can be mounted in places previously unsuitable.
Another object of the present invention is to provide such an oil cooler which has improved heat exchange between the oil to be cooled and the liquid coolant.
This and other objects are achieved by the present invention wherein an oil cooler has an oil circuit and a cooling circuit arranged in a housing with inlet and outlets. The housing has a flat, C-shaped annular shape with an axial thickness which is substantially less than its outer diameter. A bore extends axially through the entire thickness of a central portion of the housing. Engine components, such as a shaft, may extend entirely or partially into the bore.
The oil cooler preferably has a small axial thickness so that it can be mounted in a relatively narrow gap between an engine and the transmission without taking up additional structural space in the constricted engine area. The oil cooler can have relatively large radial dimensions to accommodate long cooling conduits and to have a good heat exchange.